Disclaimer: BYU is a tough team to analyze. They play a terrible schedule, so it's tough to find games in which they faced teams as good as the 'Noles. They also constantly have guys leaving for and returning from Mormon (LDS) missions. They also redshirt a ton of kids. The missions plus the redshirting has the effect of making their players old- but in a good way. Most of their starters are 22 or older. FSU has one starter older than 22, for comparison. Their guys have a physical maturity not seen elsewhere in college football (though Wake Forest has a slightly muted similar effect, since they redshirt every player).
BYU's guys have been in a college weight program for at least 4 years (and in some cases 6). Compare that to the average sophomore for FSU who has had only 1 off-season in a college weight program. Aside from the physical maturity, BYU's guys also have great mental maturity. They make good decisions, show up on time, etc., because if they don't, BYU will boot them from the team due to the LDS honor code. While their guys might not appear talented, they are good football players who show a lot of consistency.
Hard to defend their schedule from last year the only teams as good or better then Florida State was Utah and TCU, and as we saw in those games was that BYU struggled with the speed of the defense.
However the missionary statement has been debated for years and years here in Utah, and the only consensus about any advantage was a mental edge in maturity. Some times when players come back it can take the majority of them over a to get their legs back, also some go to plays and either gain a ton of weight or lose a ton of weight. This advantage is really null and void and sometimes can be a disadvantage.
Nothing to add about Max Hall from Tomahawk Nation except that he might be a better pro prospect then they think, because former BYU quarterback John Beck who has not had the success as Max Hall was and he was a early second round pick.
The running game could be much better then people think with the return of Manase Tongawho as mentioned sat out last year with academic issues and if BYU commits to the run then Unga could be a force and later on down the linie help the pass game as well.
The offensive line is a question with four new starters and now the injury to left tackle Matt Reynoldswho broke his left hand in practice, and might be able to play in the Oklahoma game but should be fine for the Florida State game. The real problem on the offense that opposing teams should know is that BYU is predictable and stubborn.
In the Utah game last year BYU was averaging over 6 yards a carry, but the coaching staff decided to force the pass and that ended up costing them five picks and a fumble by Max Hall. Also, the passing attack was predictable with Austin Collie going deep, TE Dennis Pitta runs an in or out pattern, and then the other receiver ran a post.
Return missionary McKay Jacobson and sophomore O'Neill Chambers are to step up at the receiver position. Jacobson is to try to replace Austin Collie while the word from camp is that he is fully healthy from that hamstring injury he suffered from in the spring, and looks real good.
By the end of the season Arizona took advantage and watched for those plays, because coach Bronco Mendenhall kept saying all year that "as long as we execute our plays we will be fine" which was not true. Took make BYU fans even more nervous Bronco repeated that statement at media days.
The way to attack the BYU offense is to attack the quarterback with blitzing and speed rushing the edges. This could even be more of a problem with a new offensive line with four starters.